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Proceedings Paper

A highly strained InAs/GaSb type II superlattice for LWIR detection
Author(s): Yiqiao Chen; Aaron Moy; Kan Mi; Wentao Lu; Peter Chow
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Paper Abstract

IR photo detectors are in high demand for various military and civilian applications, such as airborne surveillance, remote sensing, environmental monitoring, and spectrometry. Recently InAs/GaSb type II superlattice (T2SL) has attracted numerous R and D interest since SLS is the only IR material that has a theoretical prediction of higher performance than HgCdTe. Here we report the improvement of SL photo diodes through a new design with highly-strained type-II superlattice (HS-T2SL). The HS-T2SL consists of a highly compressively strained thick InSb layer at InAs/GaSb interfaces. The presence of coherent strain shifts the band edges such that the SL energy gap is reduced. This reduced band gap is advantageous to photodetectors because longer cut-off wavelengths can be obtained with reduced layer thickness in the strained SL. The highly compressive strain in HS-T2SL also leads to an even higher optical absorption coefficient and lower dark current. Applying this new design resistance-area product (R0A) is measured as high as 2.1 Ohm-cm2 at 85K for 14.8-μm-cutoff photo diodes without any dark current suppression barriers. The fabricated 14.5μm-cutoff photo diode shows Johnson-noiselimited peak detectivity of 8.4×1010 cmHz1/2/W at zero bias at 85K.

Paper Details

Date Published: 24 September 2013
PDF: 13 pages
Proc. SPIE 8876, Nanophotonics and Macrophotonics for Space Environments VII, 887610 (24 September 2013); doi: 10.1117/12.2025514
Show Author Affiliations
Yiqiao Chen, SVT Associates, Inc. (United States)
Aaron Moy, SVT Associates, Inc. (United States)
Kan Mi, SVT Associates, Inc. (United States)
Wentao Lu, SVT Associates, Inc. (United States)
Peter Chow, SVT Associates, Inc. (United States)

Published in SPIE Proceedings Vol. 8876:
Nanophotonics and Macrophotonics for Space Environments VII
Edward W. Taylor; David A. Cardimona, Editor(s)

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